The design, discovery, and use of new reactions is the general goal of our investigation. The reactions we propose to study are of immediate interest for the synthesis of biological processes and as models of such processes. We believe that such work will open new areas for study, provide a deeper understanding of presently known phenomena, and be of interest to fields related to chemistry. The proposed studies of dipole stabilized carbanions should provide new intermediated for organic sysnthesis as well as understanding of the mechanism of the enzymatic conversion of orotic acid to the pyrimidine nucleotides. The preparation of a new functionality, the thiocarboxo group, is proposed and would be of interest as a chemical and chemotherapeutia anslog of the diazo group. Heterophilic addition represents a new and recently recognized reaction which should be explored for its synthetic potential. Reactions which would provide new azo dienophiles and iminium ions are also under study.